Automatic switch



Dec. 27, 1932. H. JACKSON AUTQMAT'IC swiTcH Filed Sept. 22. 1930 3 Sheets-Sheet 1 Tim HEIJJE1"Z Jackscm Dec. 27, 1932.

1-1. JACKSON AUTOMATIC SWITCH Filed Sept. 22, 1930 3 Sheets-Sheet 2 InLrEn 1:11"-

. HEPZJFI Jackscm Wii 1 mt Dec. 27, 1932. H. JACKSON 1,392,511

AUTOMATIC SWITCH Filed Sept. 22, 1930 3 Sheets-Sheet 3 HEFEFFT Jackson Patented Dec. 27, 1932 uN rEDfsrATEs PATENT. orrrcr.

Hna snar iAcKson, or sit nntnnsnnstnnn, ASSIGNOR o nssocrn'rnn rntnrnonn & 'rnLEea-ArHceMPAnY, or CHICAGO; ILLINOIS, A conroaarron or DELAWARE AUTOMATIC .swr'rcn Application filed s epteniber'22 yl93o, Serial No. 483,561, and in Great Britain October 11, 1929.

The present invention relates to automatic switches for use in telephone or like systems and is more particularly concerned with.

switches of the step-by-step type arranged for operation in two directions. A switch of this type as widely used in automatic tele'ph- 1 v ony is provided with ten levels or rows of bank contacts each comprising ten sets and the switch is first operated in avertical direction to select the required level and is then rotated to select the appropriate set of c011- tacts in the chosen level. Thelsetting of such a switchis efliected by two steppingmagnets operating pawl and ratchet gearing, one magnet serving to effect the vertical motion while the other effects the rotary motion. The switch is held in its operated position by a so-called double dog which comprises a pair of mechanically connected detents one engaging in the vertical ratchet teeth and the 'otherin the rotary ratchet teeth. The return of the switch wipers to normal position is then effected by'a release magnet'which moves the double do out of en a ement Z: 3 b

energized and advances the Wipers to a predetermined position in which thedouble dog is mechanically tripped so that the switch then restores to-normal under the actionof the cup spring and gravity in'the usual manner.

The invention will be better understood fromthe following description of one method of carrying it into effect which should be taken in conjunction with the accompanying drawings. It will he understood, however, that the arrangement shownis given by way of example onlyand that various modifications to the circuitsand mechanical details could readily be made by those skilled inthe art without exceeding the'scope of the inven-i tion. v

Referrrngnow to the drawings, Figs. 1 and 2 show diagrammatic front and side elevationsof the mechanism of a switch of the type considered. :Fig. 8 is a circuit of a group selector switch, that is to say I one which respondsto, a single series of impulses and subsequently hunts automatically to find a tree line, while Fig; 4 showsa circuit of a connector switch that is to say. one which responds to two series of impulses.

Referring first tothe. mechanical construction shown in Figs. 1 and 2', it will sufiice to describe merely the modifications which have been madefrom the standard switch construction. The double dog 5, which is pivoted aboutthe axis 6 and is usually operated by the release magnet armature engag ing the part 7, is providedwith projections .8 and 9 engaging with the vertical and'rotary ratchet teeth 10 and 16 respectively. In the present construction the double dog is provided with an extended arm ll which cooperates with the cam member 12 which is secured to the shaft 13 by any suitable means. The member 12 has secured to it bymeans of the screws 14 aweb 15 which is of suchdimensions that in the twelfth rotary position of the switch shaft the web engages with the extension 11 to effect the movement of the 'clear of the associated ratchet teeth until the spring 19 is next raised onthe operation of the vertical magnet'armature whereupon the projection 18 is released and owing to the action of spring 17 thedouble dog rotates about its pivot so as to prevent the restoration of the switch. The release motion in the rotary direction is efiected in the usual manner under the control of the cup spring 21 Referring now to the circuit shown in Fig. 3, when the switch is seized over the conductors and a circuit is completed for line relay A over lead DT to earth through the dial tone transformer so that the subscriber receives the usual notification that he may operate the dial. The energization of relay A operates relay B at armature a1 and relay B at armature b1 prepares the circuit of the vertical magnet, at armature L2 connects earth to the release trunk conductor RT to hold the preceding switch and at armature b3 prepares the testing circuit. No further circuit changes take place until the subscriber transmits the next series of impulses whereupon relay A de-energizes intermittently in accordance therewith and on each de-energization completes a circuit for the upper winding of relay C and the vertical magnet VM in series. Relay C is operated in this circuit and being slow to release remains steadily energized throughout the train of impulses.

Magnet VM however responds to each inrpulse to raise the switch shaft and wipers the corresponding number of steps. The double dog springs DD are carried by the member 5 illustrated in Figs. 1 and 2 and therefore close on the first operation of the vertical magnet and remain closed until the double dog is tripped on the switch being advanced to the 12th rotary position. These springs therefore serve to close a circuit for relay G which at armature g1 completes a locking circuit for itself and at armature g2 prepares a circuit for the rotary magnet. hen relay C deenergizes at the end of the train of impulses, the rotary magnet circuit is completed and the switch wipers are therefore advanced one step into engagement with the first set of bank contacts in the selected level. The rotary magnet RM also towards he end of its stroke opens the interrupter cont-acts R thus effecting the de-energization of relay G which accordingly opens the circuit of magnet RM which therefore de-energizes also and again closes the interrupter contacts.

In case the line now connected with is busy, test wiper P will encounter earth and a circuit will again he completed for relay G which will therefore operate and cause the rotary magnet to advance the wipers a further step. This alternate operation of relay G and magnet RM continues until a free line is reached at which time wiper P will no longer find earth and the switching relay H which has previously been short-circuited will be energized in series with relay G which cannot now operate owing to the high resistance of relay H. Relay H at armature hl opens the circuit of relay B, at armature hi2 prepares a locking circuit for itself and at armatures [t3 and he disconnects line relay A and connects the wipers through. Relay B is as usual provided with a slug to render it sufiiciently slow to release so that earth may be fed back from the succeeding switch over the test wiper before it is removed at armature b2.

The connection may be further extended in any desired manner and when it is to be released the calling party will replace his re ceiver, the effect of which will be to bring about the removal of earth from the release trunk conductor. T hereupon relay H deenergizes and at armature hl completes a circuit extending over armatures a1 and b1, offnormal contacts N, both windings of relay C in series and winding of vertical magnet VM to battery. The lower winding of relay G is of comparatively high resistance so that the vertical magnet VM is unable to operate at this time but relay C re-energizes and at armature 01 connects earth to the release trunk conductor to guard the switch against seiZure until it is restored to normal and at armature c2 completes a circuit for relay G which thereupon energizes the rotary magnet over armatures 01, b2 and 2. Relay G and magnet RM now interact in the manner previously described until the switch reaches the 12th rotary position whereupon the double dog is tripped and springs DD open so as to prevent any further energization of the rotary magnet. The switch is now free to re store in the usual manner and when it reaches its normal position, off-normal springs N are opened and thus relay C is de-energized and the switch is completely restored to its original condition.

In case all the lines in the selected level should be busy the switch wipers would be advanced to the 11th rotary position whereupon the cam springs would be operated. Thereupon at springs S1 the impulsing circuit is opened and the busy hold circuit over lead BH is prepared for the right hand winding of relay B, at springs S2 relay H is shortcircuited and earth is connected to the test wiper to operate the overflow meter M which is connected to a contact engaged in the eleventh position and at springs S3 busy tone and busy flash battery from lead BT are connected up in place of dial tone to notify the calling party that he cannot obtain his connection. Release is then effected in the manner previously described when the calling party hangs up thus producing the deenergization of relay B. It may be mentioned that during the normal release movement of the switch the cam springs will be operated momentarily but the circuit is arranged so that this operation shall not prr duce any undesirable consequences. It may be mentioned also that the web 15 effecting the tripping of the double dog may readily be arranged to effect the direct operation of the cam springs.

Referring now to Fig. 4 which shows a connector switch, when the switch is taken into use, line relay A is energized over the leads and and at armature a1 energizes relay B over its lower winding. Relay B thereupon at armature blconnects earth to release trunk conductor RT'tohold the preceding switches, at armature b2 prepares a circuit for the rotary'magnet RM, at'armature b3 prepares a circuit'for'the vertical magnet VM, at armature 64 connects up the slow remains energized throughout the train of impulses. At armature 01 relay. C completes an alternative circuit for itself and the vertical magnet and subsequent impulses are extended over this circuit after the offnormal springs shift on the first step;.- At the endofi the first train of impulses relay C de-energizes and at armaturecl transfers the impulsing circuit to the rotary magnet.- Consequently the next series of impulses pro-' duced by theintermittentde-ene-rgization of relay A are routed over. armature c1, intere rupter springs R, double. dog-springs DD, (now closed) ,armatures 91, k3 and 62 to rotary magnet RM and parallel thereto, upper winding of relay E. -Relay Ewhich rendered slow to release bythe slugging effect of'its shortcircuited .lower winding ener} gizes and remains energized throughout the second series of impulses and at armature e2 closes analternative circuit for the rotary magnetin place of the original circuit which is opened intermittentlyat the interrupter springsli. Relay E also at armature 61 com pletes an alternative circuit for relay A in case busy relay G should be operated during the rotary movement and at armature 63 connects relay G to the test wiper.

In case the wanted line is busy test wiper P will encounter earth when the wipers come to rest and relay G will therefore be operated. Relay G at armature 1 opens the impulsing circuit to render any further, dialling inefiective, at armature g2 prepares a locking circuit for itself, at armature g3 connects up busy tone and busy flash battery and at armature g4 completes thebusy hold circuit for the up-- per winding of relay B. The calling subscriber on hearing the busy tone will realize that he cannot obtain his connection and will replace his receiver, thereupon effecting the deenerglzation in turn of relays A and B. A. circuit is then completed from earth over armature bl, interrupter springs R, double dog springs DD, armaturebfl, upper winding of relay E to battery so that relay E is operated and at armature e2 completes acircuit for the rotary magnet. Relay C is also operated over both its windings in series to battery through thevertical magnet and at armature c2 guards the switch against seizure and opens the short-circuit round-the lower winding of relay B so as to render this relay quick to release. RelayE now acts as an interrupter relay for the rotary magnet and the wipers. are therefore advanced until the twelfth rotary position'is reached whereupon the double dog is tripped, the double dog springs DD are opened soas to prevent further operation of the rotary magnet and the I switch is restored to normal. Relay C remains energized until off-normal springs N1 open and thus ensures that the switchshall not-be taken into use prematurely. I

' Consider now the case 1n which the called subscriber is free when his line is connected with. In this case relay G though it may have been operated during'the rotary movement will not be operated when relay E releases and accordingly ,a'circuit will be completed from earth over armatures b5 and g2, lefthand winding of relay H, armatures 63 and 64, test wiper P to battery through the cut-off relay and rotary magnet of the calledpartys lineswitch. The. cut-off relay operates to clear the called line of its normal battery and earth connections and relay Halso operates and at armature hl locks up over its'righb hand winding, at armature 7L2 opens the circuit of relay G, at armature 7L3 opens the impulsing circuit to render any further dialling ineffective, at armature ha connects direct ico earth to the'test wiper to busy. the called line,

at armatures 72 5 and 7L6 connects ringing current to the called line and at armature h7 connects up the ringback condenser so as to give the calling party ringing tone. When the wanted partyreplies, ring trip relay F is operated owingito the direct currentbridge completed across the line and at armature f1 locks up over its upper winding, at armatures f2 and f3. disconnects ringingand switches thespeaking leads through andat armature f4 prepares a circuit for the supervisory lamp CSH. Back bridge relay Dis now operated by current flow over the wanted partys line and at armature cllopens the circuit of the lamp CSH and at armatures 032 and (13 reverses the connections of relay A to conductors and forthe usualsupervisory or metering purposes. r r

' At the end of the conversation when the called'part'y' replaces his receiver, relay Dis 'de-energized'and lamp CSH is li hted so D as to give an indication should the called party he held owing to the calling party failin g to replace his receiver. hen the calling party hangs up, relays A and B are de-energized and release of the switch takes place in the manner described above.

According to the invention therefore a very simple modification to the known switch construction and circuits enables the release magnet to be dispensed with and moreover the wear on the bank contacts and rotary ratchet teeth tends to be equalized.

I claim:

1. In an electromagnetic switch of thetype in which a wiper-carrying shaft is elevated a number of steps by a pawl and ratchet mechanism, wherein a second pawl and ratchet mechanism functions to then rotate the shaft to position its wipers upon desired bank contacts, wherein restoration of the shaft to its initial position is brought about by the action of a spring and by gravity, and wherein the operation of a double dog associated with the vertical and rotary ratchet mechanisms permits the restoration to take place, the combination of actuating means upon the shaft engaging and moving the double dog for the purpose set forth, consequent to a predetermined distance of rotation of the shaft.

2. In an electromagnetic switch mechanism wherein a wiper-equipped shaft is stepped vertically and then rotated to connect its wipers with a desired set of bank contacts by consecutively controlled pawl and ratchet mechanisms, and wherein means is provided for restoring the wipers to normal along the path over which they were set, upon the operation of a double dog, the combination of means on the shaft, which acts upon said double dog to move it, for the purpose set forth, upon movement of the shaft to a predetermined position.

3. In an electromagnetic switch mechanism wherein a wiper-equipped shaft is stepped vertically and then rotated to connect its wipers with a desired set of bank contacts by consecutively controlled pawl and ratchet mechanisms, and wherein means is provided for restoring the wipers to normal along the path over which they were set, upon the 1 operation of a double dog, the combination of means on the shaft for moving said double dog to release the switch, and means enabling the operation of said shaft, after it has already positioned its wipers, to bring said means on the shaft into operative relation with said double dog for the purpose set forth.

4. In an electromagnetic switch wherein a shaft is first moved vertically and is then rotated a variable number of degrees, depending upon the particular circuit or circuits to be closed, and wherein a double dog, when operated, permits retrograde movement of the shaft back from its operated to its mitial position. the provision of means on the shaft which mechanically actuates the double dog whenever the shaft is rotated beyond a predetermined number of degrees.

In an electromagnetic switch of the type wherein a shaft carrying contact wipers is moved vertically and is then rotated to connect the wipers with adesired contact set, and wherein release of the switch is initiated by a double dog co-operating with the vertical and rotary ratchet mechanism, the combination of means on the shaft for operating said double dog as the shaft is rotated a predetermined number of degrees, and contacts operated by the double dog to prevent the shaft from being rotated further than such prede termined number of degrees.

6. In a switch structure, a shaft, means for moving said shaft endwise and for then rotating it variable distances, means for holding said shaft in its operated positions, and means on said shaft cooperative with said last means consequent to a further rotation of said shaft to disengage said holding means from said shaft to enable the shaft to be restored to its initial position.

. 7. In an electromagnetic switch mechanism wherein a wiper-equipped shaft is stepped vertically and then rotated to connect its wipers with a desired set of bank contacts by consecutively controlled pawl and ratchet mechanisms, and wherein means is provided for restoring the wipers to normal along the path over which they were set, upon the operation of a double dog, the combination of means for moving said double dog clear of the shaft consequent to the movement of the shaft to a predetermined position.-

8. In an electromagnetic switch mechanism wherein a wiper-equipped shaft is stepped vertically and then rotated to connect its wipers with a desired set of bank contacts by consecutively controlled pawl and ratchet mechanisms, and wherein means is provided for restoring the wipers to normal along the path over which they were set, upon the operation of a double dog; the provision of an extension on the double dog and a cooperating cam on the switch shaft which co-act, upon a predetermined movement of the shaft, to move the double dog clear of the shaft to enable its restoration to its initial position.

In testimony whereof I afiix my si ature.

HERBERT JACKSON. 

